Among the conventionally-known vehicle body rear structures are ones where an opening section (rear-vehicle-body opening section) through which to load baggage into a baggage compartment is formed in a rear vehicle body section and where a rear cross member constituting a part of the rear-vehicle-body opening section is disposed at a low position to facilitate loading and unloading of baggage.
In such a rear vehicle body section, the rear cross member is formed in a closed-sectional shape and joined at left and right ends to rear frames extending in a forward direction of the vehicle. Further, gussets are fixed to lower surface portions of the rear cross member located beneath the rear frames and the lower surfaces of the rear frames, and bulkheads are provided within the interior of the rear cross member, so that the rear vehicle body section can have an increased strength (see, for example, Patent Literature 1).
With the rear vehicle body section rear disclosed in Patent Literature 1, however, when an impact (load) has been input to a rear bumper beam extending along the rear cross member at the time of a read-end collision of the vehicle, the rear cross member and the bulkheads would undesirably deform. Namely, the rear bumper beam is supported by impact absorbing members provided between the rear cross member and the rear bumper beam so that the impact (load) can be absorbed by the impact absorbing members to prevent deformation of the rear cross member and the rear frames. Further, in the rear vehicle body section disclosed in Patent Literature 1, component parts required to be replaced due to the deformation can be limited only to component parts for transmitting the impact (load) to the impact absorbing members, and thus, necessary cost for the component part replacement can be minimized. However, if a greater impact (load) has been input at the time of a rear-end collision of the vehicle, it would transmit via the impact absorbing members to the rear cross member and the bulkhead, so that the rear cross member in the rear-vehicle-body opening section would deform. Therefore, there arises a need to replace the rear cross member and the bulkhead as well, which can undesirably increase the necessary cost of component part replacement following the rear-end collision.
Further, in the rear vehicle body section disclosed in Patent Literature 1, the gussets are provided on the lower surfaces of the rear frames. If the rear cross member is mounted above the rear frames conversely to the aforementioned, then the gussets can be fixed to the upper surfaces of the rear frames and the rear cross member, so that the rear vehicle body section can have an increased strength similarly to the aforementioned. However, if the gussets are fixed to the upper surfaces of the rear frames, the capacity of the baggage compartment would decrease because interior members provided along the gussets project considerably into the baggage compartment.